1. Field of the Invention
The present invention relates to a cargo platform assembly including at least one platform structure designed to be removably mounted to a longitudinally extending skid tube beneath a helicopter fuselage wherein lateral movement of the skid tube, in relation to the platform, is provided.
2. Description of the Prior Art
The use of helicopters for purposes other than just transport of passengers is becoming extremely common, especially in industries requiring the use of helicopters for transporting cargo or performing certain maintenance and repair work. Because the interior space within the helicopter's cabin is generally limited, the additional unused space on the exterior of the aircraft between the fuselage and the supporting skid tube assembly is commonly used to mount an exterior load supporting structure, such as a basket or platform. Therefore, because of the limitations of the interior space within the helicopter, and further in view of the fact that most helicopters have sufficient power to carry additional weight or cargo, it is often desired to carry relatively bulky items or extra cargo on the exterior of the helicopter in order to maximize the cargo carrying capacity. Additionally, it is often necessary to carry personnel on the exterior of the helicopter for performing certain tasks and duties, such as may be necessary during military operations, law enforcement, air rescue, or industrial maintenance and repair work.
In an attempt to provide such additional capabilities on a helicopter, several attempts have been made in the prior art to secure some type of external load supporting device to the skid assembly of the helicopter in such a manner which will not substantially interfere with the normal operation of the helicopter and attached skid assembly during takeoff, flight and landing of the helicopter. Many of these external load supporting structure in the prior art were specifically designed to support workmen or other personnel on the exterior of the helicopter to perform certain duties.
The following U.S. Patents are generally representative of the closest prior art structures related to the attachment of some type of external load supporting structure adapted for attachment to the exterior structure of the helicopter, and primarily to the skid assembly. The patent to Chavis, U.S. Pat. No. 3,904,155 is directed to a helicopter step and cargo carrying assembly adapted to be connected directly to the landing gear cross tubes extending down from the helicopter fuselage to the horizontal skid tubes. The step and cargo assembly, as disclosed in Chavis, is only supported by clamps which clamp the assembly directly to the downwardly extending landing gear cross tubes. This type of mounted connection substantially limits the weight carrying capacity of the step assembly due to the tendency of the clamps to slide down the length of the skid tube supports upon applying a sufficient force to the load supporting surface. Additionally, the strength of the clamps used in Chavis limits the cargo carrying capacity.
U.S. Pat. No. 4,637,575 to Yenzer discloses a helicopter air-mobile work platform specifically designed for working on power lines and associated tower structures. The work platform in Yenzer primarily comprises a rectangular base having a length extending a greater distance than the distance between the helicopter skid tubes such that the platform extends transversely below the helicopter fuselage across the skid tubes with a portion projecting outwardly from each of the skid tubes. While the platform in Yenzer sufficiently utilizes the space below the helicopter fuselage between the longitudinally extending skid tubes, there is still very little cargo carrying capacity outboard of the skid tubes. Additionally, the transverse orientation of the platform in Yenzer creates substantial resistance or drag during forward flight.
Regardless of the various external load supporting structures present in the prior art as generally represented by the above-noted patents, there is still a need for an efficient and effective external load supporting structure which provides for a maximum cargo carrying capacity outboard of the skid tubes which is easily accessible and additionally functions as a work platform being structured and disposed in such a manner as to support a maximum weight while minimizing the amount of drag on the aircraft during normal flight.